A typical semiconductor fabrication facility can cost billions of dollars. In view of the high capital costs associated with building and maintaining a semiconductor fabrication facility, it would be desirable to decrease the time needed to process semiconductor wafers into chips. By reducing the cycle time for chip production, more chips can be produced in less time, thus maximizing the use of equipment in a fabrication facility.
One time-consuming processing step in a chip manufacturing process is the evacuation and re-pressurization of processing chambers such as those found in many plasma processing apparatuses. For example, in a typical process for forming a silicon nitride layer on a copper conductor layer, a semiconductor substrate having a copper layer is placed in a first processing chamber in a first plasma processing apparatus. The first processing chamber is evacuated to low pressure and the copper oxide at the surface of the copper layer is removed while the semiconductor substrate is in the first processing chamber. After the copper oxide is removed, the first processing chamber is re-pressurized to atmospheric pressure and the semiconductor substrate is removed from the first processing chamber. The semiconductor substrate is then transferred to and is placed within a second processing chamber in a second plasma processing apparatus. Once the semiconductor substrate is in the second processing chamber, the second processing chamber is evacuated to low pressure. A silicon nitride layer is then formed on the surface of the copper layer while the semiconductor substrate is in the second processing chamber. After the silicon nitride barrier layer is formed on the copper layer, the second processing chamber is re-pressurized to atmospheric pressure and the semiconductor substrate is removed from the second processing chamber.
Sometimes, load-locks are used to transfer substrates into and out of a processing chamber. A substrate may be placed in a load-lock and the load-lock may be pumped down and re-pressurized prior to inserting the substrate into or taking a processed substrate out of a processing chamber. A typical load-lock houses a smaller space than a processing chamber and consequently takes less time to evacuate and re-pressurize.
A significant amount of time is needed to transfer the substrate between the first and second processing chambers, re-pressurize the processing chambers (or load-locks), and evacuate the processing chambers (or load-locks). It would be desirable to reduce the time associated with one or more of these steps to reduce the amount of time needed to process the substrate.
One way to reduce the processing time for semiconductor substrates is to use a cluster tool. Cluster tools have been used to reduce the time associated with evacuating and re-pressurizing different processing chambers. A typical cluster tool includes more than one processing chamber and a transfer chamber. Different processes can be performed on a single substrate in respectively different chambers without removing the substrate from a low pressure environment. In a typical cluster tool, a robot in the transfer chamber transfers a substrate from one chamber to another at low pressure. There is no need to evacuate or re-pressurize a chamber when inserting the substrate into the processing chamber or removing the substrate from the processing chamber.
Although cluster tools improve processing efficiency, it would still be desirable to further reduce the time associated with substrate processing. For example, while cluster tools reduce the time associated with evacuating and re-pressurizing different chambers, time is still needed to transfer the semiconductor substrate between the different processing chambers. Moreover, only one process per chamber is performed in a typical cluster tool, thus limiting the processing capacity of the cluster tool.
It would be desirable to reduce the amount of time associated with processing a substrate such as a semiconductor substrate. Embodiments of the invention address this and other problems.
Embodiments of the invention relate to methods for processing a substrate such as a semiconductor substrate.
One embodiment of the invention is directed to a method for processing a substrate in a processing chamber in a processing apparatus. The method comprises: (a) placing a substrate in the processing chamber, wherein a first layer comprising a conductive material and an oxide layer are on the substrate; (b) removing the oxide layer while the substrate is at a first temperature in the processing chamber; and (c) forming a second layer on the first layer while the substrate is at a second temperature in the processing chamber, wherein the second temperature is different than the first temperature.
Another embodiment of the invention is directed to a method for processing a substrate in a plasma processing apparatus. The method comprises: (a) forming a remote plasma outside of a processing chamber in the plasma processing apparatus; and (b) performing a first process on a substrate in the plasma processing chamber using the remote plasma; and (c) performing a second process on the substrate in the plasma processing chamber.
Another embodiment of the invention is directed to a method for processing a substrate in a processing chamber in a processing apparatus. The method comprises: (a) placing a substrate in the processing chamber; (b) performing a first process on a substrate in the processing chamber while the substrate is at a first temperature and is spaced from a pedestal comprising a heating or a cooling element; and (c) performing a second process on the substrate while the substrate is at a second temperature and is on the pedestal.
Another embodiment of the invention is directed to a method for processing a substrate in a processing chamber in a plasma processing apparatus. The method comprises: (a) placing a substrate in the processing chamber, wherein a conducting layer and an oxide layer are on the substrate; (b) removing the oxide layer while the substrate is at a first temperature and is disposed above a pedestal comprising a heating element; and (c) moving the substrate until the substrate contacts the pedestal at a second temperature that is higher than the first temperature; and (d) depositing a dielectric layer on the conducting layer.
These and other embodiments of the invention are described in detail below with reference to the Figures and the Detailed Description.